Certain fields of industry such as particularly the field of agro-food industry, require nowadays the installation of workstations disposed in microfiltered atmospheres so as to avoid any microbiological contamination of the products. These new requirements translate to workstations disposed remotely and interconnected by means of a tunnel or a chamber with bacteriologically-controlled atmosphere, so as to permit the movement of the products or containers from a point P to a point P' in the absence of any contamination of microbial origin. However, these devices also have a certain number of drawbacks, particularly because the products are transported on a conveyor such as a conveyor band or a conventional belt which generally has not undergone any decontamination other than periodic cleaning and disinfection. In spite of everything, in certain cases the belts will be, in the course of their return run toward the point of deposition of the products, washed and then dried so as to have clean belts but which are not sterilized or nearly sterilized. A second process to overcome this drawback of contamination of the products by the conveyor consists in enclosing the products with an external covering which is constituted for example by a gas-proof barrier so as to protect the product from all contamination. Obviously, this type of process is cumbersome and limits the handling of the product.